Taking 39 target trees and 210 competitive trees in Galang National Wetland Park in southeast Tibet as the research objects,based on field survey data,the competition index of species in Pinus armandii community was calculated by Hegyi individual competitive indices(CI) model,and the regression analysis method was used to establish the functional model of DBH of target trees with the whole stand,associated tree species and intraspecific competition intensity.The results showed that:1) There was a significant power function relationship between DBH and tree height of P.armandii;2) The intraspecific and interspecific competition index of P.armandii accounted for 54.68 % and 45.32 % of the total competition index respectively,intraspecific competition was dominant in the community;3) The order of compe-titive species among P.armandii species was Quercus aquifolioides> Picea likiangensis var.linzhiensis> Pinus densata;4) The DBH of P.armandii had a significant negative correlation with the competition index of the whole stand,associated tree species and intraspecific,and the model can effectively predict the intraspecific and interspecific competition intensity of P.armandii;5) P.armandii population.belongs to the growth type,need to strengthen the protection of mature forest to prevent faults.